Safety pilot control



Feb. 10, 1953 H. F. scHoENr-ELD ErAL SAFETY PILOT CONTROL Filed Sept.22. 1948 3 Sheets-Sheet l Feb. 10, 1953 H. F. scHoENFr-:LD Erm.2,627,867

SAFETY PILOT CONTROL Filed Sept. 22. 1948 3 Sheets-Sheet 2 IN VEN TORS.

1F05/mana J Jm/Z/z/S/er Henry A c/memfeld A TTPNEKS.

Feb. 10, 1953 H. F. scHoENFl-:LD ErAL 2,627,857

SAFETY PILOT CONTROL Filed Sept. 22. 1948 3 Sheets-Sheet 3 Ill lll

/ IN VEN TORS BY @MKM TTUAPA/EYS.

Patented Feb. 10, 1953 naar UNITED STATES PATIENT '()l'lffIC'Ili SAFETYSPiLoT CONTROL 10 Ciaims.

his invention relatesto improved controls for gas burners, particularlycontrols embodying simple, reliable heat-responsive units of the typehereinafter described.

In the operation of gas burners, there is an element of danger arisingoutof the possibility that, following niterruption of the iiow of gas inthe system or failure'of the pilot burner to continue to function forsome other reason, gas may be admitted to and discharged unburne'd bythe main burner. In' some types ci burners, provision is made forautomatically cutting oi the supply of gas to the main burner but noprovision is made for cutting oli the passage of gas to the pilotburner, thus permitting leakage oi the unburned gas from thepilot`burner. In an eort to remedy these deci'en'cies, controls have beenproposed in the past that would cut off the supply of gas to both themain and pilot burners; however, such controls have proven to becomplicated, unreliable, or both.

The present invention makes possible, and has for its principal lobjectto provide, aY simple, reliable control for glas burners that operatesto cut on" the supply of gas to both main and pilot burners in the eventthat somev abnormal condition inhibits operation of the 'main'burnen Afurther Vobject is to proviclea control that may without difficulty beinstalled, actuated, and adjusted to different conditions of operation.other object is to provide a control in which operation of the actuatingmechanism is easily initiated from the exterior of the device. Stillanother object isl to provide' a Asimple, reliable heat-responsive unitfor controls of these' and other kinds that may be installed, adjustedand, if necessary, replaced, all with a minimuml of effort.

The invention is illustrated in the accompany ing drawing, in which:

Figure 1A is a sectional plan, with parts ielevation, of a controlconstituting a'preierred embodiment of the invention;

'Figure 2 is a'verticalv section, with parts in elevation, along line2-2 of Egurel;

Figure 3 is a verticalsection, with parts in elevation, along line 3 3of Figure l;

Figure 4 is a transverse vertical section, `with parts in elevation,along line 4-4 of Figure l;

Figure 5 is a detail, on an enlarged scale, of the sealing assemblyappearing in elevation in 1Figure 4;

Figure 6 is a diagrammatic perspective show ing the actuating mechanismoi Figures l, 3 and g 4 in me erst com) position;

Cil

2 Figure 'l isa similar view showing the same actuating mechanism in thesecond (pilot) position;

Figure 8 is a similar View showing the same actuating mechanism in thethird (on) position; Figure 9 is a side'view of the outer cam lin theposition illustrated in perspective in Figure 8;

Figure `10 illustrates the control of Figures 1 to 4 as employed with agas burner used for heating water;

Figures v11,y 12 and V13' show, in'sectional plan, a :modified controlwithin the purview of the invention and illustrate theactuatingmechanism thereof in the"off, pilot and on positions,respectively;

Figure 14 isa transversegvertical section on line Ill-I4 oi Figure V11;and

Figure 15 is' a side veW of the open link forming part of the actuatingmechanism of the modified control of Figures' 11 to 14, inclusive.

The control illustratedin: Figures 1 to 9,'inelusive, is characterized,among other things, by a body or block havingjtwo` separate passagewaystherethrou'gh. In each. of vsaid. passageways is located aspring-pressed check valvebiased toward closed position. Arsinglejajctuajtorj serves both check valves, unseating Vthem seriatim`When the control is putinto operation. In normal operation, theactuator isV held byl a thermallyoperated detent' in a position inVwhich both valves are unseated. Upon the development oi a conditionwhich inhibits' continued operation of the main burner, the actuatorfunctions to permit the check valves to seat, the seating being seriatimbut in reverse order as compared with the Vorder in which the valves areunseated. Referringnow to Figures 3- and 4, body l, which preferablytakes the form of a block machined from bar stock `or a casting, isprovided with a wide threaded inlet 2-admitting gas from the suppl-ysystem. On the opposite side of body l is a narrotvthreaded outlet 3through which the gas so admitted passes to the main burner. Betweeninlet 2 and outlet 3 is a smooth connecting bore d, whichV is narrowerthanin-let 2 and. of substantially the same diameter as outa let 3. Atthe base of inlet2 is an annular shcul der 5 which servesas a valve.seat for main Vval-ve 6. The latterconsists, inv `addition to thevalvebody, of an 0-ring packing 1-,- Ia, hollow stud 8, which, if desired.maybe solid, spring centering means 9, and a coil spring Illwhichabutsfagainst and is vplaced. under compression by the inner en dofva coupling member Il whichv serves/as a cap or retainer for the valveassembly.

As shown in Figures 1, 2 and 4, body I is further provided with a secondthreaded inlet I5, a smooth connecting bore I6 of smaller diameter, thelatter constituting an extension of inlet I5, and a communicating crossbore I1 drilled from the exterior of body I at right angles to inlet iand connecting bore I6. The outer end of cross bore I1 is closed by asuitable plug. Between inlet I5 and connecting bore I6 is an annularshoulder I 8 which serves as a valve seat for pilot valve I 9. Thelatter is generally similar to main valve 6 in that it is provided withan 0ring packing 20, is biased toward seating position by a coil spring2 I, and is retained in place by a coupling member 22 which is similarto, but smaller than, coupling member li. Mounted for movement with buton the opposite side of pilot valve i9 is a plunger 23 which extendsthrough a suitable opening in the wall 24 separating connecting bore I6from connecting bore 4. As indicated in Figures 1 and 4, plunger 23projects well into connecting bore 4. Surrounding plunger 23 is thesealing assembly 25, shown in detail in Figure 5, which comprises an0-ring packing 25, an overlying washer` 21 and a coil spring 28 whichforces the O-ring packing 26 into sea-ling contact with plunger 23 andwall 24.

The purpose of inlet I5, connecting bore I6 and cross bore I1, is toprovide a passageway admitting gas to pilot burner tube 33. i

Figures 2 and 4 illustrate the manner in which an orifice of theconventional type may be inserted in body I between cross bore I1 andpilot burner tube 33. A threaded bore 36 extending from the exterior ofbody I to a point in proximity to cross bore I1 provides access to asecond threaded bore 3I of smaller diameter. The latter communicateswith a smooth connecting bore 32 which extends through body I inprolongation of threaded bores 30 and 3I. Pilot burner tube 33 havingopenings 34 is brazed or screwed in place in connecting bore 32 at apoint spaced from orice 35. Between orifice and the inner end of pilotburner tube 33 is an air opening 31 which permits air to mix with thegas passing through orice 35 into pilot burner tube 33. Access toorifice 3I may be had by removing oriiice cap 3B, which serves to sealbore 30 against the escape of gas when the control is in operation.

The actuating mechanism or actuator for main valve 6 and pilot valve I9is located in body I in the relationship shown in Figures l and 3.

A transverse bore communicating with bore 4 in the first of the twoabove-described passageways extends from one side to the other of bodyi. At opposite ends of bore 40 two bushings 4I are mounted, as bybrazing, in gas-tight relation to the ends of bore 40. Within bushings4I is located a. shaft 42 which is so mounted as to permit it to have aconsiderable degree of rotary movement and which projects beyond thesides of body I. Rigidly affixed to sha-ft 42 at a point midway of bore43 is an inner cam 43, shown also in Figure 4. On opposite sides ofinner cam 43 and abutting bushings 4I are sealing assemblies 44generally similar to sealing assembly 25. On the same side of body I aspilot burner tube 33 is an outer or locking cam 45 which is rigidlyaixed to the projecting end of shaft 42. On the opposite end of shaft 42is an actuating knob or dial 45 having indicia thereon which serve todisclose the position of the actuator at any given time. Within knob 46is a return spring 41 of the torsion type, the ends of which are fixedto knob 46 and body I.

As shown in Figures l and 3, a post or rod 50 parallels pilot burnertube 33, being mounted in body I in such manner as to preclude thepossibility of movement other than the hereinafter described movement ofits free end. Preferably, post 50 is solid and fabricated from type 430stainless steel having a co-e'icient of expansion of 0000065; however,it may be of hollow construction and, if desired, of some other materialhaving a higher or lower co-efiicient of expansion. Adjacent post 50 isa generally L-shaped primary element 5I which has its outer end 52 atthe end of the long leg thereof shaped to conform to and welded ontopost 50 at the outer end thereof. Primary element 5I has a relativelyhigh degree of expansibility, being preferably of type 43'/ stainlesssteel with a co-efcient of expansion of .0000095; however, any othersuitable material with a co-efflcient of expansion of the same order ofmagnitude may be used instead; e. g., type 421 stainless steel.

The short leg 53 of L-shaped primary element 5I extends at right anglesto the long leg thereof in a position to overlie outer cam 45. It isprovided with a longitudinally extending slot (not shown) through whichextend two screws 59 which serve to attach adjusting strip 51 to shortleg 53. Adjusting strip 51 is coextensive as to width with short leg 53of primary element 5I and is mounted for adjustment lengthwise of shortleg 53 by suitable manipulation of the screws 59. At one end ofadjusting strip 57 is a tang 53, struck up from strip 51, which servesas a cam stop for outer cam 45 in a manner hereinafter to be described.

Welded to primary element 5I at the unsupported inner end thereof, butat a point short of the point at which short leg 53 extends therefrom,is a secondary element 54 which, like post 50, preferably is, but neednot necessarily be, of type 430 `stainless steel with a co-efilcient ofexpansion of 0000065. Therefore, as compared with primary element 5I,secondary element 54 is characterized by limited expansibility. At theend of secondary element 54 opposite the unsupported inner end thereofis an L-shaped bracket 55 one shank of which is brazed, welded orotherwise aiixed to secondary element 55 and another shank of which,extending at right angles, is received and welded in place in a slot 56milled in post 50 at a point intermediate the supported and unsupportedends of primary element 5I.

Post 50, primary element 5I and secondary element 54 are so related, bybeing mounted in the manner above described, as to permit ofconsiderable transverse movement but little lengthwise movement ofeither element. As the fla-me from pilot burner tube 33 strikes the nearside of the free end of post 50, the supported end of primary element5I, and such parts (if any) of secondary element 54 as are exposed toit, primary element 5I tends to lengthen as a result of its relativelyhigh coecient of expansion. However, because of the relatively lowcoefficient cf expansion of secondary element 54, which places a limiton eiective lengthwise expansion of primary element 5I, the latter tendsto bow toward post 50, an action which has the net eiect of imparting agenerally clockwise or upward movement to the short leg 53 of primaryelement 5I and the unsupported end of secondary element 54 as seen inFigure l.

This transverse movement of the parts is somewhat accentuated by thelimited expansion occurring in post 50 as a result of localized heatingnear the free end thereof on the side next gesmeerto pilot burnertube'33`. The side'of thefree end of post 50 near the pilot burner tubereaches a higher temperature than the opposite side; thus, the sidenearthe-pilot'burner tube expands 'more than the opposite side. As aresult, the freefend of post 5d tends to bend away from pilot burnertube 33 in a generally clockwise or downward direction as seen in Figurel, thus imparting to the supported outer end of 'primary element 5I atur/ning force which has the effect of accentuating the generallyclockwise or upward movement of short leg 53. Such movement of short leg53 produces corresponding movement in strip 51 vand tang or cam stop 58.

By modifying the materials and proportions of the several parts,different operating-characteristics, particularly different operatingltimes, Vcan be developed in the heatresponsive unit. For example, thelimited expansion of the free end of 'post 5c can be enhanced by using atype of stainless steel 'or some other Vsuitable 'material having aco-eicient of expansion "higher than the characterizing type zl'3'0stainless steel. Simik larly, by varying the dierence in length betweenprimary element 5I and secondary element 5d, it is possible to increaseor decrease the sensitivity of the heat-responsive unit-andtherefore ofthe control as a whole. With due regard to these and similar factors,the present invention thus makes it possible to provide a 'controlwhich, unlike 'the controls of the prior art, is capable or" reliableoperation even at very high ambient temperatures.

Referring now to Figure 9, outer cam 45, which receives tang, takes theform of a shallow disklike member that may be cast as shown cr machinedfrom an originally circular blank. Of its four quadrants, only twoadjacent quadrants, .A and B, remain largely or entirely intact. Of athird quadrant C, nothing remains except a quarter-circle 5i) near thecenter. The fourth quadrant D contains a guiding slot 52 terminating inan inwardly extending notch or recess A63 located at the inner endofslot'62 but formed in quadrant A rather than in quadrant D. The innerwall of guiding'slot 62 vis dened by a quarter Circlet! which adjoinsand is of thesame radius Aas the duarter circle-69 remain-ing at thecenter of quadrant C.

On the far side of guiding lslott? is`an arcuate member 65, locatedlargely in quadrant D, oi which the inner edge 64 forms `the vouterwallof guiding slot 62. The radially extendingend face B1 of arcuate member55 cooperates with tang 58 in a manner to be described, as -does alsothe radially extending face-66 located `at thepoint Where quadrant Band'quadrant C adjoin. Together with the recess 63 at the inner end ofguiding slot 62, the semi-circular portion'il 'is .adapted to serve aspart of a' detent mechani'sm'which includes tang 58.

As shown Yin diagrammatic vfashion in VFigures 6?, 7 and 8, the actuator'for main valve .sand pilot valve I9 consists essentially of .shaft A2,.inner cam d3, outer cam i5 'and knob 4%. As indicated in Figure 6, `inthe first (oi") position, valves 6 and I9 are seated on theirrespective'valve seats 5 and I3. In this positicn,.the lobeofinner camd3 extendsdownward out of contact with Istud. 8 on main valve 6 and outof contact with plunger 23 on pilot valve IS. Tang 58 on adjusting strip51 vis in contact with radiallyv extending face 56 formedfby outer camdat thepoint wherey quadrants B andC adjoin. This zris therelationshipof parts,mcr e particularly fthe yrelationship of the actuator to mainvalve '6 and pilot valve le, when the control unit .is 'iirst installed:in the mai-n burner.

When itis desired Yto place the control `in operation, kknob .45 is`.rotated counterclockwise through an arc 'of .'90,`which brings thelobeof inner cam 43 .into contact withplunger .23 of pilot valve I9 and thusforces the latter away from its seat on annular @shoulder I8. At theVsame time, outer ca'm 45, being rigidly .aiixed .to :shaft d2, isrotated throughfan'arcsofie", which serves to bring `rad'ialiend `face61 on arcuate'member 65 into contact with tang 58. This .is `the `second(.pilot.) position, and .is .illustrated in Figurev 7. With the 'partsin thisrelationto each other, Agas escaping through openings 3.4V in.pilot burner tube 33 `canine ignited. VIn @this position, spring .ditends to return .the'parts :to their zoriginalA Dosition, so thatcontinuing :eiort must be .exercised through :knob '46 .to ykeep :pilotvalve I9 unseatcd.

As the free end of `post "50-and the supported endofgprimaryfelem'ent 51.heat up under .the inuence of the pilot -flame, short leg 53 ofprinmary element 5I moves .laterallyas already described, carrying withit--adjusting strip 5l and tang 5B. With knob :d5 heldin the second(pilot) position, short Aleg .53, adjusting `strip 51 and tang 58 moveinward across radial end face 61 of arcuate member ,55 ,intoregistrywith guiding'slct'62. `This action, v4whichnormally requires fromnfteento thirty `Iseconds :for its :completion, permits the actuator vto vbe.rotated through va further arc of iby'continued counterclockwisemovement .of :knob 4t. At this point the actuating mechanism-,arrives:at-the relationship indicated inFigure x8, .illustrating the third on)position.

In this position, the lobe on inner .cam d3 is in contact with-bothgplunger ,123 von pilot valve I9 and stud d on main valve 5,; so.that both pilot valve te and main valve 6 .zare now unseated. rThe iiowcf gas .past `main lvalve''which results permits the flameemanatingfromi openings St in pilot burner tube 3.3 to :ignite thegasescaping from the mainxburner. Ain the'meanwhil'e, continued lateralmovement of short leg 53 of 'primary element 15|, adjusting strip :57,and tang 55 brings the latter 'into recess 163and, by detent action,prevents return spring Hiram restoring the parts to 'their originalposition.

Upon the development-of an abnormal condition which inhibits continued.operation yofthe main burner, vby which ,is .imeantthatfboththe flameat thefmain burner and that emanating from openings 34 in .pilotiburner.tube '33. have been inadvertently extinguished, jprimary element 5Itends to 'contract'. reversing the lateral travel of short .leg y53,adjusting strip 5l, and tang 53. Movement of tang 58 toward post 15d inconsequence ofv this contraction .of primary element 5I results in-disengagement of tang and outer cam at the :innerend vofsguiding slott2. Thisipermits progressive :returnof the vactuator,including.innerxcamit to :its original position, v'with' consequent:seating of main vvalve 6 and pilot valve Iil in that -f'crden Tang 5&3rides on surfacesv i; I and 'Eil 'cfr lthe .inner semi-circular portionof vouter `cain'ltaunitil `'it Yiinally abuts radial face Se, at :which:point the parts again :in their originalfposition.

The control illustrated .in Figures luto 9, -inclusive, maybeinstalled-in' the system as vindicated ,in Figure/10. Sc installed,labracket-lt holds body I inloperating position. Conduit'ii .suppliersVgasv :for @pilot burner `tube' `T33 to body I Conduit "I2 supplies gasfor main burner I4 to body I. Conduit 'I3 supplies gas from body I tomain burner i4. The control as so incorporated in the system is inaddition to the control provided by the usual thermostat acting inresponse to changes in temperature in the water or other medium beingheated by main burner '54.

A modiiied control is illustrated in Figures 1l to 15, inclusive. Suchcontrol, like that illustrated in Figures 1 to 9, inclusive, ischaracterized, among other things, by two separate passageways through abody or block, a springpressed check valve, biased toward closedposition, in each of said passageways, and actuating mechanism, operablemanually from the exterior of the control, for unseating the valvesseriatim. Cooperating with the actuating mechanism and serving to holdboth valves in unseated position is a heat-responsive unit similar tothat illustrated in Figures l to 4 but lacking the angularly extendingportion comprising short leg 53 of primary element 5I. In otherrespects, the modified heat-responsive unit comprising post |50, primaryelement |5| and secondary element |54 is much the same as theheat-responsive unit illustrated in Figures 6 to 8, inclusive.

As indicated in Figures 11 to 13, inclusive, the modified controlcomprises a body |||I machined or otherwise formed from bar stock or acasting. It is provided with a wide threaded inlet |62 receiving gasfrom conduit 'I2 (Figure l0), a narrow threaded outlet |03 permittinggas so received to travel thence to the main burner, and a smoothconnecting bore IM. Inlet |62 and outlet |l3 extend at right angles toeach other, being coupled together by connecting bore |86. At thejunction of connecting bore IUI! and inlet |62 is an annular shoulder|05 serving as a valve seat for main valve |06. The latter consists, inaddition to the valve body, of O-ring packing It?, hollow stud |08,spring centering means |09, and coil spring im, all of which areretained in place by action of coupling member III on spring H0.

At the opposite side of body IGI is an opening in which is received abushing ||2 brazed in gas-tight relation in body IBI. Through suchbushing extends a pin ||3, one end of which is received in stud |08 onmain valve |06 and the other end of which projects beyond the body ||lI. Located between stud |08 and bushing ||2 is a sealing assembly H4generally similar to the sealing assembly shown in Figure 5.

A second passageway through body IGI is formed by threaded inlet I l5,which receives gas from conduit 7| for the pilot burner flame; by asmooth connecting bore I6, relatively narrow as compared with inlet H5;by a cross bore drilled from the exterior of body ||l| and plugged atits outer end; by a threaded bore I I8 paralleling connecting bore IIE,and by a smooth outlet bore ||9 in which is mounted pilot burner tube33, the latter being brazed or screwed in place. Located approximatelyat the center of body IEI is criiice |25, the same being inserted andremoved through threaded bore ||8. The latter is sealed against escapeof gas by oriiice cap IZI. Extending transversely through body I|l| at apoint in proximity to the discharge side of orii'lce |23 is air inlet|22, shown in Figure 14.

Located at the junction of inlet ||5 and connecting bore ||6 is anannular shoulder |23 serving as a valve seat for pilot valve |24. The

latter is generally similar to main valve |66, being characterized by anO-ring packing |25,- a coil spring |25 biasing the pilot valve to closedposition, and means taking the form of coupling member |27 for placingspring |26 under compression. On the opposite side of body IGI is abushing 28 brazed in position in gas-tight relation in body li. Throughbushing |28 extends a pin |29, the inner end of which, surrounded by asealing assembly |36 generally similar to the sealing assembly shown inFigure 5, abuts against valve |25.

Rigidly mounted on the projecting outer end of pin |29 is a button |3|by which force may be applied to pilot valve |24 to unseat the sameagainst the action of coil spring |28.

Overlying button 13| is an open link |32, shown also in Figure l5, bywhich main valve IBB may be actuated in similar manner. Near its openend, link |32 surrounds pilot burner tube 33, one branch |35 of the linkoverlying button |3| and the other branch |36 extending parallel tobranch |35. At its other end, link |32 has a slot |37 in which isreceived a bolt-like member |33 fastened to pin H3. Cooperating withboltlike member |33 and serving to clamp link |32 in place between themis a nut |34. Adjustment of link |32 toward and from pilot burner tube3S is made possible by slot |31, bolt-like member |33 and nut |34.

As shown in Figures 11 to 13, inclusive, primary element |5| andsecondary element |5I| are squared oir at their unsupported ends asindicated at |38, this to provide a detent adapted to engage the natouter face of branch |36 of link |32.

With the parts in the position indicated in Figure 1l; that is to say,with the parts in the cold position, the control is installed much ascontemplated by Figure 10. When it is in order to initiate operation ofthe burner, force is applied manually to depress button |3|, whichresults in immediate unseating of pilot valve |24. This action permitsgas to enter inlet H5, connecting bore HS, cross bore |I'I, threadedbore IIB, outlet bore H9, and pilot burner tube 33. The iioW o1n gasthus established permits lighting of the pilot ame. Localized heating ofpost |53 and the supported end of expansible element IE! results ingrowth of primary element |5| with consequent transverse movement ofsquared-oil end |33. At this point, the parts are in the positionindicated in Figure 12, the main valve being closed and the pilot valve|24 being open.

As squared-0E end |38 approaches branch |35 of link |32, it becomesnecessary to apply manual force to, and thereby to depress, link |32,which action serves to unseat main valve |36. Because branch |35 of link|32 overlies button |31, it is then no longer necessary to continue toapply manual force to button |3|: the same end is accomplished by theapplication of manual force to link |32. Unseating of main valve |06,with attendant inward movement of the pin IIS and link |32, permitssquared-off end |38 of primary element |5| and secondary element |52 tocome into engagement with and ride upon the hat outer face of branch |35of link |32. This state of affairs is indicated in Figure 12 andcontinues until there is an interruption in the operation of the mainburner.

If, however, an abnormal condition develops to inhibit operation of theburner, including the pilot flame, primary element |5| contracts, withresulting reversal of the original movement. The resulting inward travelof squared-off end |33 of primary element and secondary element |54disengages link |32, permitting main valve |26 and pilot valve |24 toseat. Such seating takes place substantially simultaneously. Thus theparts return to the cold position indicated in Figure 1l, precluding allnow of gas until such time as manual actuation is again employed torestore the system to operation.

Advantages of the invention as expressed in each of the twoabove-described embodiments include the possibility of installation ofthe control in almost any position, a feature which follows from the useof spring-pressed check valves rather than valves which depend upon theaction of gravity. The controls illustrated in Figures 1 to 9 andFigures 11 to 14 are easy to manufacture, simple to assemble, andreliable in operation. They lend themselves to many uses other than theindicated use in connection with the heating of water; in fact, certainparte thereof such as the elements of the heat responsive unit, i. e.,post 59 or |53, primary element 5| or ISI, and secondary element 54 or|54, as the case may be, lend themselves to installation in controls ofother types. A high degree of reliability, coupled with flexibility,characterizes both the heat-responsive units and the controlsthemselves.

Numerous changes may be made without departing from the inventiveconcept and it is therefore desired that the invention should beaccorded the scope contemplated in the appended claims, which areintended to define whatever features of patentable novelty reside in theinvention.

We claim:

1. A control for a gas burner comprising a valve body provided with avalve alternately permitting and preventing now through the valve body;a post rigidly mounted on the valve body; a relatively expansibleelement of elongated form one end of which is supported from the postand the other end of which is unsupported, such unsupported end beinglocated in proximity to but spaced from the valve body; a relativelyineXpansible element attached to the expansible element at a pluralityof widely separated points one of which is near the unsupported end ofthe expansible element; and, mechanically connected to the valve, amanually movable latching member located in the space between the valvebody and the expansible element, the unsupported end or the expansibleelement having a coacting portion serving as a detent for said manuallymovable latching member.

2. A gas burner control as in claim'l in which the manually movablelatching member takes the form of a flat-surfaced link.

3. A gas burner control as in claim 2 in which the link is adjustabletoward and from the detent.

4. A control for a gas burner comprising a valve body provided with avalve alternately permitting and preventing flow through the valve body;a post rigidly mounted on the valve body; a relatively expansibleelement of elongated form one end of which is supported from the postand the other end of which is unsupported, such unsupported end beinglocated in proximity to but 'spaced from the valve body; a relativelyinexpansible element attached to the expansible element at a plurality`of widely separated points one of which is near the unsupported end ofthe expansible element; and, mechanically connected to the valve, lamanually movable cam member located in the space between the valve bodyand the expansible element, the unsupported end of the expansibleelement having a coacting portion serving as a detent for said manuallymovable cam member.

5. A gas burner control as in claim 4 in which the unsupported end ofthe expansble element includes a part that acts as a cam stop.

6. A gas burner control as in claim 5 in which the cam includes a slotreceiving that part of the expansible element that acts as the cam stop.

7. A -control for a gas burner comprising a valve body provided with aplurality of functionally independent valves, each of said valvesalternately permitting and preventing flow through the valve body; apost rigidly mounted on the valve body; a relatively expansible elementof elongated form one end of which is supported from the post and theother end of which is unsupported, such unsupported end being located inproximity to but spaced from the valve body; a relatively inexpansibleelement attached to the expansible element at -a plurality of widelyseparated points one of which is near the unsupported end of theexpansible element; and, mechanically connected to each of the valves inthe valve body, `a manually movable latching member located in the spacebetween the valve body and the expansible element, the unsupported endof the expansible element having a coacting portion serving as a detentfor said manually movable latching member.

8. A gas burner control as in claim 7 characterized by the presence ofmechanical means for seating the valves substantially simultaneously.

9. A gas burner control as in claim 7 characterized by the presence ofmechanical means for seating the valves seriatim.

10. A gas burner control as in claim 7 characterized by the presence ofmechanical means for unseating the valves seriatim.

HENRY F. SCHOENFELD. RAYMOND J. SMITHISLER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,326,247 Zengel Dec. 30, 19192,027,458 Tepas Jan. 14, 1936 2,064,909 Hahn Dec. 22, 1936 2,179,633Jenkins Nov. 14, 1939 2,240,950 Hahn May 6, 1941 2,308,272 English Jan.12, 1943 2,363,525 Higley et a1 Nov. 28, 1944 2,381,926 Ray Aug. 14,1945 2,385,155 Newell Sept. 18, 1945 2,420,078 Higley May 6, 19472,426,786 Newell Sept. 2, 1947 2,427,935 Vandenberg Sept. 23, 19472,487,968 Higley Nov. 15, 1949

